Health and Medical News and Resources

General interest items edited by Janice Flahiff

Prolonged TV Watching’s Health Outcomes

From the  18 July 2011 US National Library of Medicine (NLM) Director’s Comments article

Watching television for more than two hours a day is associated with significantly higher risks of type 2 diabetes, cardiovascular disease and death from all causes, finds a comprehensive analysis of prior research recently published in Journal of the American Medical Association.

Eight international studies suggest two hours of daily television viewing is associated with a 20 percent higher risk of type 2 diabetes, a 15 percent higher chance of cardiovascular disease, and a 13 percent increased risk of all-cause mortality for men and women.

The findings suggest each two hour increment of daily TV watching results in an absolute risk of 176 new cases of type 2 diabetes, 38 new cases of fatal cardiovascular disease, and 104 new cases of all-cause mortality among 100,000 persons each year.

The researchers’ findings are based on a meta-analysis of eight studies about the broader health impacts of television watching.

Meta-analyses assess a cluster of previous research studies within a highly similar area. The findings sometimes suggest commonalities or aggregate patterns, which are more evidence-based than the findings from individual studies. Meta-analyses also suggest areas where more comprehensive research is desirable – and sometimes identify new research agendas.

The studies were done in four nations and published between 1970-2010. The authors note the current study is the first quantitative and systematic assessment of television viewing and health research.

In the meta-analysis of television viewing’s health impacts, its two authors only assessed research undergirded by large sample sizes. All eight studies featured long durations of participant follow-up, and well-established prospective study methods. Prospective studies follow the health of a cohort, or group of similar persons, over time and often assess the consequences of a common exposure (such as television viewing) on health outcomes.

The authors, from the University of Southern Denmark and the Harvard School of Public Health, explain the first generation of research tied prolonged television viewing with unhealthy eating habits and less exercise. The authors add a second generation of research suggested an association between TV viewing and biological risk factors, such as obesity and adverse lipid levels.

The current findings represent a third generation of research that suggests an association between prolonged television viewing and disease risks, including type 2 diabetes and cardiovascular disease. Moreover, the current findings suggest prolonged television viewing is linked to an elevated risk of death from all causes.

Within the article, the authors discuss how TV viewing displaces time on other activities, such as sleeping, exercise, and reading. The authors explain future researchers need to better contextualize the impact of TV viewing and health outcomes. For example, they suggest future research might assess the health impacts of TV watching in comparison with a range of the activities it displaces.

The authors also suggest reversing current emphases to note the impact of reducing TV watching on health outcomes. They write (and we quote): ‘Further study is needed to determine whether reducing prolonged TV viewing can prevent chronic disease morbidity and mortality’ (end of quote).

While MedlinePlus.gov does not have a health topic page devoted to the health impacts of TV viewing, a medical encyclopedia article about television watching is available. The article explains the American Academy of Pediatrics recommends no television viewing for children under age two, and fewer than two hours per day for older children.

Of course, the current research suggests the impact of prolonged television viewing may be deleterious to adult health. It will be interesting to see the extent that future research is consistent with the eight studies identified in the current meta-analysis and how these yield suggestions for a more therapeutic use of our time.

To find the encyclopedia article, type ‘television watching’ in the search box on MedlinePlus.gov’s home page. Then, click on ‘television watching.’

Before I go, this reminder……. MedlinePlus.gov is authoritative,….. free…. does not accept advertising …and is written to help you.

To find MedlinePlus.gov, just type in ‘MedlinePlus.gov’ in any web browser, such as Firefox, Safari, Netscape, or Explorer.

We encourage you to use MedlinePlus and please recommend it to your friends. MedlinePlus is available in English and Spanish.

Your comments about this or any of our podcasts are always welcome. We welcome suggestions about future topics too!

Please email Dr. Lindberg anytime at: NLMDirector@nlm.nih.gov

That’s NLMDirector (one word) @nlm.nih.gov

July 22, 2011 - Posted by | Uncategorized | , , , ,

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